diff --git a/tests/common/eq.rs b/tests/common/eq.rs
index 4a882bb..fc69dec 100644
--- a/tests/common/eq.rs
+++ b/tests/common/eq.rs
@@ -436,7 +436,7 @@
             tokens.push(TokenTree::Token(DUMMY_SP, Token::Not));
         }
         let lit = Lit::Str_(Symbol::intern(&contents));
-        let mut tts = vec![
+        let tts = vec![
             TokenTree::Token(DUMMY_SP, Token::Ident(Ident::from_str("doc"), false)),
             TokenTree::Token(DUMMY_SP, Token::Eq),
             TokenTree::Token(DUMMY_SP, Token::Literal(lit, None)),